Desperate will give brainlist and thanks "When Franklin Roosevelt first entered politics he was wealthy, charming, astoundingly good-natured, ambitious, and optimistic - but not very serious. Perhaps everything had come to him too easily. In his boyhood and youth and early manhood he had not known suffering. Now he knew. Now there were steel braces on his legs and a current of steel in his veins."

What is meant by "a current of steel in his veins"?

Question 1 options:

He was made of metal.

He was struck by lightening.

He was strong willed.

He had metal poisoning.